How to properly report Blender 2.8 crash and what files to send?
Blender can open the bug report page for you, and with 2.80 it also automatically fills in the blender build info and operating system data for you. Then you just have to fill in the details of what happened and how it can be reproduced.

Note that random crashes that can't be reproduced would be impossible for a developer to find and fix. The easier it is for a developer to make blender crash, the easier it is to find what is causing it. The more info you can give, including a sample file that can make getting the error easier, the easier it is for the developers to fix.

While the position may change over time, you can find Report a Bug in blenders Help menu.